Various types of exposure systems using photolithography techniques are proposed as systems for recording predetermined patterns on printed circuit boards or on substrates of flat panel displays such as liquid crystal displays.
As one of such exposure systems described above, for example, an exposure system that scans a light beam on a substrate with a photoresist applied thereon in the main scanning and sub-scanning directions while modulating the light beam with exposure image data representing an exposure pattern to form the exposure pattern on the substrate is proposed.
As such exposure systems, various types of exposure systems that use, for example, a spatial light modulation device, such as digital micro-mirror device (DMD) or the like, are proposed, in which exposure is performed by modulating the light beam with the spatial modulation device according to image data.
As one of such exposure systems employing the DMD described above, an exposure system for forming a desired image on an exposure surface by moving the DMD in a predetermined scanning direction relative to the exposure surface, and inputting image plotting data corresponding to multitudes of micro-mirrors to the memory cells of the DMD according to the movement of the DMD in the scanning direction to sequentially form image plot points corresponding to the micro-mirrors of the DMD in time series manner is proposed as described, for example, in Japanese Unexamined Patent Publication No. 2004-233718.
Here, it is assumed, for example, the case where exposure patterns are formed on a multi-layer printed circuit board. The multi-layer printed circuit board is heated in pressing process to paste the respective layers together and the board may sometimes be deformed by the heat. Thus, in order to accurately align the exposure patterns on the respective layers, it is necessary to form the exposure pattern on each layer by taking into account the deformation of the board.
Also, for flat panel displays, the substrate is heated when color filter patters are exposed, so that the substrate may be stretched or shortened by the heat and the recording position of each color of R G B may be displaced. Therefore, it is necessary to form an exposure pattern by taking into account the deformation of the substrate.
In the case where the same exposure pattern is formed on many substrates or the like, if exposure image data are generated in real time according to the amount of deformation of each substrate, and the exposure is performed based on the exposure image data, the production efficiency may be reduced due to prolonged time required for generating the exposure image data according to the amount of deformation of each substrate.
Consequently, a method for obtaining exposure image data without decreasing the production efficiency is conceivable, in which deformations of the substrates described above are assumed, then a plurality of different types of exposure image data is generated in advance by an image processing unit according to the deformations of the substrates and stored in an exposure unit, and when an exposure is actually performed, information related to the amount of deformation of a substrate is obtained and the exposure image data corresponding to the amount of deformation of the substrate are read out and used for the exposure.
The present invention relates to improvements in the method and apparatus for obtaining image plotting data used for the aforementioned image plotting method and apparatus.